System for the transmission of intelligence.



svsnzm FOR THE TRANSMISSION OF mmueaucsi A Patented Apr. 27, 1915.

APPLICATION FILED MAY 13.1914- l l l ldml M @mW/my message to be sent.

; UNITED STATES PATENT onnicn.

EDWIN H. COLPIT'IS, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

SYSTEM FOR THE TRANSMISSION INTELLIGENCE.

Be it known that I, EDWIN H. COLPITTS, a subject of the'King of Great Britain, residing at East Orange, in the county of Essex and State of New Jersey, have invented cer tain new and useful Improvements in Systems for the Transmission of Intelligence.

This invention relates to systems for the transmission of intelligence, in which the amplitudes of successive electrical oscillations of high frequency are varied in ac-.

cordance with the lower frequency forms of the messages delivered.

Its object is to simplify the mechanism and to strengthen the efiectiveness of the apparatus required for the production of the "modulated oscillations.

To these ends the invention embodies a re-.

of sustained electric or electromagnetic waves of high frequency transmitted from the sending station.

The single device used to perform the tw functions referred to may be a repeater, preferably a repeater of the audion type, wherein the output circuit is connected with the input circuit, this arrangement, with proper adjustment of devices in the circuit, resulting in the production of sustained high frequency oscillations. By varying the potential in the input circuit, as for example by connecting a transmitter or other device for sending a message in circuit with one of the electrodes, say the grid, of the audion,

the sustained oscillations, it has been found,

are then modulated in accordance-with the The message may be received. or recorded in any desired manner at the distant station. Several embodiments of the invention will be set forth in the following detail description taken in connection with the accompanying drawings, wherein- Figure 1 illustrates a system ofcircuits Specification of Letters Patent.

' Patented Apr. 27, 1915.

Application filed my 18, 1914 Serial N 0. 839,318RyEIs To all whom it may concern:

embodying the invention; and Figs. 2, 3 and 4t are modified circuits therefor.

Like parts are designated alike in the several figures.

Referring first to Fig. 1, an audion 1, the elements of which are inclosed in an evacuated vessel, as usual, is arranged with its output anode or plate 2 connected through the primary windings 3 and 4 of repeating coils 5 and 6 to the negative terminal of the heated filament or cathode 7 of the audion.

Included in this output circuit may be lo-.

cated a battery 10 and, as required, adjustable devices such as the condensers 8 and 9. Bridged across the circuit, to feed battery current to the plate 2, is a coil of high impedance 11. The filament 7 is heated by current from the battery 12. The input electrode or grid 13 of the audion is connected, 7

through the secondary windingl f of a red i peating coil 15 to the negative terminal of the filament 7, 'and included in thisthe input circuit, there maybe located a battery 16. The secondary winding 17 of the repeating coil 6 is connected through an adjustable condenser 18 with the input circuit, one wire leading to the grid 13 and the other wire to the negative terminal of the filament 7. I

The primary winding 19 ofthe repeating co l 15 may be connected in circuit with the secondary winding 20 of another repeating primary winding 22 of which coil 21,- the is connected in circuit with abattery 23 and a sending device, which, asshown, may be a telephone transmitter 24. The repeating coil 5 has a' secondary winding 25, the terminals of which lead to the antenna of a wireless system or to the line of a Wire circuit, according to the particular use to which the apparatus is put. y 4 i The operation of the system illustrated in Fig. 1 is as follows: The audion l-is rendered active by the heated filament 7, which emits a stream of negative ions across the space intervening between it and the positively charged plate 2. This stream passes through the interspaces of the grid; The battery 10,

acting through the resistance of the coil 11,

fluctuate at a very high frequency, by reason of the interaction between the input and output circuits through the repeating coil 6. The frequency of the sustained Oscillations produced by this arrangement may be varied by adjusting the capacities of the various condensers in the circuit. The high frequency currents in the output circuit are transmitted by the repeating coil 5 into the line or antenna to which the secondary winding 25 may be connected.

By means of the telephone transmitter 24;, the amplitude of the sustained oscillations is modified or modulated in accordance with sound waves which are of a lower order of frequency. This may be explained as follows: At the normal potential of the battery 16 impressed on the grid 13, the sustained oscillations are produced at a constant amplitude. At a higher potential, due'to a positive impulse from the winding 14, the current in the output circuit is increased, and the amplitude of the high frequency oscillations is greater. Conversely, at a lower potential, due to a negative impulse, the oscillations become lesser in amplitude than normal. Thus each pulsation of potential, caused by speaking into the transmitter 24, is effective in producing a corresponding variation in the amplitude of oscillations of current, and therefore of energy in the output circuit and likewise in the line or antenna.

In Fig. 2 is shown an arrangement difiering from that of Fig. 1 in that the battery 10 thereof, corresponding to the like num-. bered battery in Fig. 1, is connected in se- -ries with the high impedance coil 11 in bridge of the output circuit. The arrangement is also diflerent in that the battery 16 is included in a bridge of the input circuit in series with an adjustable resistance 26.

In Fig. 3 is illustrated a modified circuit in which the battery 10 is included in series with the high impedance coil 11 as it is in Fig. 2, but primary windings 3 and i of the repeating coils 5 and 6 are connectedin parallel with relation to each other instead of in series as in Figs. 1 and 2.

In Fig. 4 an arrangement is shown in which two audions 1 and 1 are used. Here the battery 10 is connected to a central point in the winding of the high impedance coil 11 the outer terminals of which are connected to the two plates 2 -and 2 respectively of the two audions. Battery 16 is likewise connected to a midpoint of an adjustable resistance 26, the outer terminals of which are connected to the two grids 13 and 13 In the system of Fig. 4-, therefore, the battery 10 tends to supply asteady flow of current through both audions from the plates 2 and 2 tothe two filaments"? and 7", re spectively.- The battery 12 supplieseurrent to both of the filaments 7 and 7'". The op eration is such that the impulses from repeating coils 6 and 15 produce at any instant of time opposite potential. variations on the grids 13 and 13", and these opposite potential variations produce an effect which is cumulative in the output circuit to which the plates 2 and 2 are connected.

What is claimed is:

1. The combination with a generator of high frequency current, comprising a re" peater and an input and an output circuit therefor united with each other, said peater having an electrode located in sai input circuit; of a transmission line unite with said output circuit, and a source low frequency potential variations connected to said electrode.

2. The combination with an audion liar ing a filament, a plate and a grid, an input circuit connected with the grid and an one put circuit connected with the plate; of an inductive connection between said output and said input circuits ada ted to the pr duction by said audion or sustained high frequency oscillations, and a sending device, adapted 'for producing signaling impulses of low frequencies, connected with said put circuit.

3. The combination with a generator of high frequency current, comprising a r peater, an input and an output circuit there for and a connection between said circuits; of a transmission line united with said output circuit, and a sending device, adapted for producmg signaling impulses of low frequencies, connected with said input cir cuit.

l. The combination with a generator of high frequency current, comprising an emu uated vessel, means for producing a mi ionization. in said vessel, and aninpru. sar

an output circuit interconnected to re it upon each other; of means connected with said lnput circuit for producing low frequency potential variations in said input 3 a circuit.

. 5. The combination with a generator of high. frequency current, comprising an. evacuated vessel, means for producing a state of ionization in said vessel, and. an iu- 311.3

high frequency current, comprising evacuated vessel, means for producing a state of ionization in said vessel, and l input and an output circuit connected each other: of means included in said cir cuits for adjustingthe frequency of said our rentg and a source of low frequency pot tial variations connected with said iny circuit for controlling the amplitude of the high frequency currents dove oped by said generator.

7. In apparatus of the kind described,

the combination of an evacuated vessel and means, including a cathode, for producing a state of ionization in said vessel; of an input anode and an output anode in said vessel; an output circuit connected to said output anode and including an adjustable condenser and a source of continuous current, an input circuit connected to said input anode and inductively connected to said output circuit, and means connected with said input circuit for producing low fre quency potential variations in said input circuit.

8. The combination with an audion havmg an input circuit and an outputcircuit inductively connected with each other; of 20 means connected with said input circuit for producing low frequency potential varia tions in said input circuit.

In witness whereof, I hereunto subscribe my name this 15 day of May A. 1)., 1914.

EDWIN H. COLPITTS. 

